I know of no systematic attempt to demonstrate the efficacy in use of any framework described in any major success study. In the absence of hard evidence, it is far more likely that whatever benefit practitioners might have perceived or realized has been the consequence of some or all of a form of placebo effect (you expect it to help, so you perceive that it does), a Hawthorne effect (the mere act of focusing on something you were neglecting improves performance), or random variation (otherwise known as luck).
Author: Michael E. Raynor
Source: The Conference Board Review
Subjects: Best Practices, Management, Success / Failure